1. Field of the Invention
The present invention relates generally to a key telephone system and, more particularly, to a key telephone system which enables data communications over an integrated services digital network (ISDN) line.
2. Description of the Related Art
In the field of key telephone systems arranged to effect data communications over line wires which accommodate ISDN lines, a system has not yet been proposed which is equipped with a speed matching function (the function of effecting speed conversion prior to transmitting over a 64-Kbps ISDN line with a B channel data received at a low speed such as 9600 bps from a personal computer or the like.
The disadvantage of such a conventional system is that, even if the key telephone system is fully digitized and the ISDN line is accommodated in the line wire, it is impossible to realize data communications with a data terminal such as a personal computer connected to an extension of the system.